Air Pollution and Childhood Respiratory Allergies in the United States

BACKGROUND: Childhood respiratory allergies, which contribute to missed school days and other activity limitations, have increased in recent years, possibly due to environmental factors. OBJECTIVE: In this study we examined whether air pollutants are associated with childhood respiratory allergies in the United States. METHODS: For the approximately 70,000 children from the 1999-2005 National Health Interview Survey eligible for this study, we assigned between 40,000 and 60,000 ambient pollution monitoring data from the U.S. Environmental Protection Agency, depending on the pollutant. We used monitors within 20 miles of the child's residential block group. We used logistic regression models, fit with methods for complex surveys, to examine the associations between the reporting of respiratory allergy or hay fever and annual average exposure to particulate matter <= 2.5 mu m in diameter (PM2.5), PM <= 10 mu m in diameter, sulfur dioxide, and nitrogen dioxide and summer exposure to ozone, controlling for demographic and geographic factors. RESULTS: Increased respiratory allergy/hay fever was associated with increased summer 03 levels [adjusted odds ratio (AOR) per 10 ppb = 1.20; 95% confidence interval (CI), 1.15-1.26] and increased PM2.5 (AOR per 10 mu g/m(3) = 1.23; 95% CI, 1.10-1.38). These associations persisted after stratification by urban-rural status, inclusion of multiple pollutants, and definition of exposures by differing exposure radii. No associations between the other pollutants and the reporting respiratory allergy/hay fever were apparent. CONCLUSIONS: These results provide evidence of adverse health for children living in areas with chronic exposure to higher levels of O-3 and PM2.5 compared with children with lower exposures.